One sure sign of fall is a beautiful V formation of Canada geese flying south for the winter. But what about the hundreds of them that hang around, leaving their signature messes in our parks? Why didn’t their travel alarm clocks go off?

It turns out that we’re “blessed” with a largely non-migratory subspecies known as the Giant Canada goose. They were hunted almost to extinction, for the large amount of meat and soft down these birds can yield. In 1962, preservationists discovered a small, tag-end population in Missouri and determined to bring the species back. Government breeding programs took up the challenge and, to ensure their viability, disbursed them all over the country. In a perfect example of well-intentioned plans gone wrong, they’ve now overrun us. We’ve created them. They’re ours.

I’ll suggest ways of keeping geese off your lawn, but all you’re doing is moving them on to someone else’s.

The Giant Canada geese love big lawns. In fact, they’re the perfect suburbanites. Those that had any inclination to fly south soon gave that up, as the spread of parks, golf courses and large manicured lawns gave them plenty of green shoots and grasses to feed on. New ponds gave them water, in communities where hunted isn’t allowed. You see them grazing along the mowed edges of highways, with streams behind. The global warming trend is keeping them happy, too.

According to the Cornell Lab of Ornithology, Canada geese have become a problem in more than 100 urban areas in 37 states, where their populations range in size from several hundred to more than 27,000 (for example, Minneapolis, Minn.). Studies of these populations have implicated their feces in the eutrophication of small ponds and lakes, as well as the contamination of school yards, parks and boating and swimming areas. There’s also the possibility of disease transmission to humans from direct contact with fecal material or contaminated water. (For more about the history of Canada geese in our area, I recommend Connecticut Birds, by Joe Zeranski and Tom Baptist.)

Local governments and private homeowners are asking scientists to come up with management plans for the non-migratory population. Hunting culls geese in rural areas and keeps them from congregating in large flocks. But even with current estimates of 2.6 million Canada geese being harvested annually through legal hunting, their population continues to grow.

To achieve a balance between too few and too many geese, managers are employing various techniques, both lethal and nonlethal. In urban and suburban areas, these include harassing geese that are trying to nest; destroying nests and eggs (although the geese might start again); or addling the eggs to keep them from developing. The most common way of addling eggs is to cover them with corn oil so that air can’t reach the embryo. The goose will generally stay on the nest, so you’ll have no goslings that season.

The simplest way of driving geese away from parks and lawns is to change the landscape. Geese like quick access to water and open grassy feeding areas that allow them to see potential predators approaching. So plant bushes and dense high grasses along your pond or stream, line it with boulders or put up a fence. Turn more of your lawn into meadow, which eliminates the green shoots they eat. Advocate for more shrubs and bushes around the lakes in our parks, to unsettle their sense of security. Tall trees near lakes and ponds make it hard for them to land.

If you’re thinking of putting in a lovely pond at the end of your open lawn, don’t.

Giant Canada geese tend to return to the place where they hatched to start families of their own. So ridding them for a season or two could move them along permanently – into someone else’s park.

John Hannan is director of development for Audubon in Connecticut and can be reached at jhannan@audubon.org.